---
title: "The synthesis of nitric oxide gas from nitrogen and oxygen gases is represented by the following chemical equation.  \\[ \\text{N}_2(g) + \\text{O}_2(g) \\rightleftharpoons 2\\,\\text{NO}(g) \\quad K_c = 4.0 \\times 10^{-31} \\text{ at } 298\\text{ K} \\]  A sample of \\(\\text{N}_2(g)\\) and \\(\\text{O}_2(g)\\) is introduced into a rigid container at \\(298\\text{ K}\\) and allowed to reach equilibrium. Which of the following correctly identifies the predominant species in the container at equilibrium and provides the valid justification?"
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url: "https://nerd-notes.com/ubq/119721/"
date_modified: "2026-08-21T08:12:08+00:00"
---

# The synthesis of nitric oxide gas from nitrogen and oxygen gases is represented by the following chemical equation.

\[ \text{N}_2(g) + \text{O}_2(g) \rightleftharpoons 2\,\text{NO}(g) \quad K_c = 4.0 \times 10^{-31} \text{ at } 298\text{ K} \]

A sample of \(\text{N}_2(g)\) and \(\text{O}_2(g)\) is introduced into a rigid container at \(298\text{ K}\) and allowed to reach equilibrium. Which of the following correctly identifies the predominant species in the container at equilibrium and provides the valid justification?

The synthesis of nitric oxide gas from nitrogen and oxygen gases is represented by the following chemical equation.

\[ \text{N}_2(g) + \text{O}_2(g) \rightleftharpoons 2\,\text{NO}(g) \quad K_c = 4.0 \times 10^{-31} \text{ at } 298\text{ K} \]

A sample of \(\text{N}_2(g)\) and \(\text{O}_2(g)\) is introduced into a rigid container at \(298\text{ K}\) and allowed to reach equilibrium. Which of the following correctly identifies the predominant species in the container at equilibrium and provides the valid justification?

- **A.** Predominantly products, because a small value of \(K_c\) indicates that the rate of the forward reaction is significantly greater than the rate of the reverse reaction.
- **B.** Predominantly products, because products are placed in the numerator of the equilibrium constant expression, which requires a large product concentration.
- **C.** Predominantly reactants, because a value of \(K_c \ll 1\) indicates that the equilibrium concentrations of the reactants are much greater than the equilibrium concentration of the product.
- **D.** Predominantly reactants, because the forward reaction ceases to occur once equilibrium is established, preventing further product formation.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119721/*